Safety treadle



April 14, 1953 E. M. MAHARDY SAFETY TREADLE Filed April 5, 1949 2 SHEETS-SHEET l INVENTOR.

A EDWARD M. MAHARDY April 14, 1953 E. M. MAHARDY 2,634,625

SAFETY TREADLE Filed April 5, 1949 2 SHEETS-SHEET 2 Patented Apr. 14, 1953 SAFETY TREADLE Edward :M. Mahardy, Frankfort, N. Y., assignor to Utica Drop Forge & Tool Corporation, a. corporation of New York Application April 5, 1949, Serial No. 85,680

This invention relates tosafety devices in general, and relates particularly to a safety treadle to operate the control treadle of a machine.

Many types of machines, among which are drop forge hammers and presses, are controlled. by a foot treadle which the operator presses to initiate a work cycle of the machine. These treadles usually operate by a downward pressure of relatively small intensity in order that the operator may press the treadle many times during the day without undue fatigue.

Particularly in drop hammer forge operations, there is a great danger of unintentional operation of the machine by accidental pressure on the treadle, and more often by workpieces of on siderable weight droppingon the treadle. The danger to workmen is evident.

Therefore, an object of this invention is to provide a safety device toprevent unintentional-operation of a treadle controlled machine.

Another'object of this invention is to' provide a safety treadle to positively lock the control treadle until intentionally released.

A further object of this invention is to provide a lock for a treadle, and a hooded trigger release forthelock. r I I A still further object of thisinvention is to pro-' vide a lock for a treadle and a longitudinally extendingopening with a release trigger for a lock residing within the opening in a position to be released by pressure of the-toe portionof the operators shoe. i

Other objects and 'fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in "Which:-

Figure 1 is a broken away portion of-a drop hammer base illustrating the control treadle of the hammer and a safety treadle constructed according to the principles of this invention;

Figure 2 is a rear View of the safety treadle illustrated in Figure l;

Figure 3 is a longitudinal sectional view of the safety treadle in a locked position holding the control treadle against unintentional actuation;

and

Figure 4 is a longitudinal sectional'view illustrating the method of releasing the safety treadle for operation of the control treadle and machine.

The details 'of construction in the particular embodiment of the invention herein illustrated are best set forth in Figure 3 of the drawings. The fundamental features ofthis invention may easily be incorporated into a standard control treadle and-employ parts of the standard control 3 Claims. (01. 74-539) treadle, but preferably the safety treadle will be constructed as an attachment to be placed on the control treadle. This is particularly true in drop hammer operation. The foot pedal of punch presses and similar machines may be constructed in accordance with the principles of this invention without the addition of auxiliary foot plates.

Particularly fordrop hammer operation, the Figure 3 illustrates a base portion in a, fixed position relative to the base IU of a drop hammer, and a foot plate l4 reciprocably mounted on the base portion for movement relative to the base Ill. The base portion in this particular embodiment, includes an upright member in the form of a post I1. A floor guide IB is provided to give the post I! a firm foundation because the floor surrounding drop hammers is generally of earth or rough boards. The post .I I is provided with a round base portion 33 in order to permit the post ll to rock on the floor guide, and the floor guide is may be spiked to a-woqden floor or welded to suitable brackets extending from the base I.

In order to prevent binding between the foot plate l4'and the post IT, a long bearing is provided by passing the post I! through an opening 30 in the foot plate I 4, and providing a bearing It a distance away from the opening 30. A bracket i5, as best illustrated in the Figure 2, is welded, or otherwise suitably secured, to the foot plate l4 and carries the bearing I6, as illustrated. Thus, the foot plate I4 is bearinged on the post H by the opening 30 and the bearing I6.

The foot plate [4 is attached to a control treadle I lot the hammer by means of bolts l9 which extend through the treadle II, the foot plate l4, and the bracket l5, as best illustrated in the Figure 2. The bolts l9 are drawn tight and thus cause the treadle l I and the foot plate M to move as one unit. That is, the treadle ll cannot be moved without a correspondingmovement of the foot plate l4, and conversely, any movement of the foot plate M will move the treadle II. 'In the particular installation illustrated, a notch 3| is cut in the'tre'adle H for the post H. An alternate provision would be a hole of considerably larger size than the diameter of the post l1.

When the machine is not in operation, the treadle l l and foot plate l4 are in the elevated position illustrated in Figure 3. In order to prevent unintentional operation of the machine, the safety treadle is locked in the position illustrated in Figure 3. The locking function is provided in this embodiment by a recess. 20 on the post I! to provide a lock surface or ledge 2|. A two-finger c'atchineniber 22 serves as the'lock portion of a releaseable lock means including the catch '22 and release trigger 24. The lower surface 23 of the bracket [5 serves as a lock surface on the bearing portion of the foot plate I4. The trigger 24 is pivotally mounted on the foot plate M by pivot pin 25, and is thereby adapted to operate in a slot 32 in the foot plate l4. A pivot pin 21 interconnects; thecatch 22 and the release trigger- 24; The catch 22 is urged into a locking position between the surfaces 2| and 23 by two springs 26, as illustrated in the Figures 2 and Thus, the catch 22 will automatically loci; the foot plate 14 against relative movement in relation to the post 11 upon alignment of therecess. 29 with the catch 22 in the-positionillustratediin Figure 3. The trigger 24 is constructed to extend above the surface of the foot plate I51r Whensthe;

' tratedinFigureB} because. the. catch. 22 interlocksbetween .the surfacesZ I and 23. Therefore; to operate the treadle I I andinitiate aworkcycle inthe;hammer, the operator may place his foot uponthe foot, plate I4 and, thereby press; the treadle .2 t, intov the, position, illustrated in Figure 4, to withdraw the catch. 22. out of engagement between the surfaces 2! and 23.- Thereafter, by continued; downward pressure, the foot plate I4 may bemoyed, downwardly on, the post I! and thus pivot the treadle. H aboutthe pivot. l3 to operat s hehammer. Ihhamm r devices of this type, .the ontrolhar 2 s. r d .iht rnonroperate hepos t nibr. m n n h hammer itse1f.-,

The efor after. h perator.- rele ses the pres,- surefrom the foot plate I 4, thetreadle- I] will tend-1130 pivotabout the; pivot l3'andmove the footplate l4.upw-ar dly. relativeto-thepin H. The foot, plate; M will move freely upwardly until the catch .22, registers, with the. recess 20 and, re.- engagesbetween, the surfaces-2L and 23 to lock he. parts-a a nst; re a i s-mov m nt;

Although-a device. as thus far described has been-foundto. greatly minimize the accidental operation,of the machine'by unintentional pressure placedv upon the control treadle, a further feature forms a part of-this invention to: render the r-safety treadle virtually foolproof against re,- ea i.. hefg thla e; L4. nd a t a on f h rea le, L by alli g;W0rkp e s,andc1umsy feet. Th fe tureis a.hood. .28.0v r he r ger. 24 to hr vide. a. protesting: ah rand. prevent. 11 35: teptional 'fo es.... r.om. d pressing. the. trigger. 2.4-. Thus, he. he 1.; fi h ides-a. lon tudinallv ex; hso hiha wi hthe releasing tri ger ZAree ding; W thin he-machi e a. sition o. e eleas y. pressured. thetoe port .on. .of. the ner t f hoe. hser edwi hih ev penin ut s-- s elded. ea nstaH. un nt ntional: forces. There ore, faheavypi ce f W rkfan from th op ra rs. hu s, Q liiihe: operator or h s helper tc eht r messes. d wnwar ly th.v mot 11 hsa e y adlewhil ad usting-their dies, th

Iiiv

4 unintentional forces are shielded against contact with the trigger 24. A very deliberate insertion of the operators foot into the longitudinal opening provided by the hood 28 is required in order to release the foot plate 14 and operate the machine.

Generally, the preferable material for the hood 28 1s sheetsteel; Therefore, whensuchmaterial is used' for the hood 28; it is preferableto provide a bumper 29 of rubber or other suitable soft material to avoid harm to the operator.

Although the invention has been described in its preferred form with a certain degree of particularity, it:'is;und'erstood that the present disclosure; ofthe preferred form has been made only by way of example and that numerous changes in,.th e,details. of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What. is claimed is:

1--.v A- safety dev-icefor a reciprocable footoperated control member .of' an. industrial machine comprising, a post member,,means.to mountrsaid post. member adjacent the controlmember of, a machine.- ina relative;- fixedz' position-. av pressure receiving plate member, meansfor; securing said pressure receiving plate member. to saidcontrol member, said plate member thereby: having, a reciprocable; path; of. movement between: a first and second limit, saidipostmember having, one latch lock. surface, a: catch: carried: by said plate member, said. latch lock surface and catch positionedto engage only when the plateisisubstan tially at said first limit, of movement, saidplate having an.openingtherethrough, a: trigger mem.- ber pivotally mountedwithin the confines of. said plate in-said opening; means drivingly connecting said trigger to said catch, said triggerhaving" a first pivotal position extending-partially above the; surface of; saidplate, asecondposition flush with the surface of; said-plate resilient; means urging said triggerrmeans1 andbatch; tosaidfirst position, said;tr igg er' means; in.z'saidfirst;position adapted to intercept a force;- directed towardzsaid plate to thereby be pivoted to said secondjposije tion, and upon-movement of; said: trigger to said second position'the plate :and control member are freed of said postand-.freetomove without. re striction throughout-"the, entire range between said first and second-limits.

2. A safety device for a reciprocablerfootzope erated control member of; an: industrial machine comprising, a post member, meansto mounttsaid postmemberin .a relatively fixed position, a pressure receiving plate" member, means mounting said plate member for-movementin areciprocable-pathbetween a first-and second: limit, said p t member; havin one. latch; lock; surface,=. a catch; carried by" said. plate; member; said' latch lock. surfaceand; catch-1 positioned: to. engage-only when the plate is substantially'rat; saidEfir qfimovemena.saidplatezhaving an opening h hrough a: tr ger: member pivotallwmounted wi hin the confines; of; said; Plates-313M113 opens ing, means drivingly connecting-said trigger; to. said catch, 2 said; trigger; having a, firscr-. pivotal position ;;extendin%-partially; above thesurfaceaof said plate; al-second; position fiLISh WitIl' thQiSHL- face-of said plate, resilient" means urging;. said ger. meansand catchtosaid first. position, said trigger. means in said. first. position. adapted; to ntercep a. fOl'Qfie'diIffiQtBd; toward. said: plates-tohereby beaniyotedi to;saidrsecond;ppsitiom and upon movement ofr..saicl- ;-;trigeer. to; said. second.-

position the plate and control member are freed of said post and free to move without restriction throughout the entire range between said first and second limits.

3. A safety device for a reciprocable foot operated control member of an industrial machine comprising, a pressure receiving plate member secured to said control member and thereby operable through a reciprooable path between a first and second limit, a post member extending from said plate to a fixed surface, said post member having one latch lock surface, a catch carried by said plate member, said latch lock surface and catch positioned to engage only when the plate is substantially at said first limit of movement, said plate having an opening therethrough, a trigger member pivotally mounted Within the confines of said plate in said opening, means drivingly connecting said trigger to said catch, said trigger having a first pivotal position extending partially above the surface of said plate, a second position flush with the surface of said plate, resilient means urging said trigger means and catch to said first position, said trigger means in said first position adapted to intercept a force directed toward said plate to thereby be pivoted to said second position, and upon movement of said trigger to said second position the plate and control member are freed 5 of said post and free to move without restriction throughout the entire range between said first and second limits.

EDWARD M. MAI-IARDY.

10 References Cited in the file of this patent UNITED STATES PATENTS 

